This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
1xRTT CDMA2000 1X (IS-2000),
3GPP third generation partnership project
ACLR adjacent channel leakage ratio
A-MPR additional maximum power reduction
BW bandwidth
CA carrier aggregation
CC component carrier
CDMA code division multiple access
CE control element
DL downlink (eNB towards UE)
eNB E-UTRAN Node B (evolved Node B)
E-UTRAN evolved UTRAN (LTE)
IMT-A international mobile telephony-advanced
ITU international telecommunication union
ITU-R ITU radiocommunication sector
LTE long term evolution of UTRAN (E-UTRAN)
LTE-A long term evolution advanced
MAC medium access control (layer 2, L2)
MME mobility management entity
MPR maximum power reduction
NCE network control element
Node B base station
NS network signaling
NW network
PDA personal digital assistant
PHR power head room
P-MPR power management maximum power reduction
RF radio frequency
RTT round trip time
RX receiver
SGW serving gateway
TX transmitter
UE user equipment, such as a mobile station or mobile terminal
UL uplink (UE towards eNB)
UTRAN universal terrestrial radio access network
As is specified in 3GPP TR 36.913, LTE-A should operate in spectrum allocations of different sizes, including wider spectrum allocations than those of Rel-8 LTE (e.g., up to 100 MHz) to achieve the peak data rate of 100 Mbit/s for high mobility and 1 Gbit/s for low mobility. It has been agreed that carrier aggregation is to be considered for LTE-A in order to support bandwidths larger than 20 MHz. Carrier aggregation (CA), where two or more component carriers (CCs) are aggregated, is considered for LTE-A in order to support transmission bandwidths larger than 20 MHz. The carrier aggregation could be contiguous or non-contiguous. This technique, as a bandwidth extension, can provide significant gains in terms of peak data rate and cell throughput as compared to non-aggregated operation as in LTE Rel-8.
A LTE-A terminal with reception capability beyond 20 MHz can simultaneously receive transmissions on multiple component carriers. A LTE Rel-8 terminal can receive transmissions on a single component carrier only, provided that the structure of the component carrier follows the Rel-8 specifications. Moreover, it is required that LTE-A should be backwards compatible with Rel-8 LTE in the sense that a Rel-8 LTE terminal should be operable in the LTE-A system, and that a LTE-A terminal should be operable in a Rel-8 LTE system.
FIG. 1 shows an example of the carrier aggregation, where M Rel-8 component carriers are combined together to form M×Rel-8 BW (e.g., 5×20 MHz=100 MHz given M=5). Rel-8 terminals receive/transmit on one component carrier, whereas LTE-A terminals may receive/transmit on multiple component carriers simultaneously to achieve higher throughputs through bandwidths.
With further regard to carrier aggregation, what is implied is that one eNB can effectively contain more than one cell on more than one CC (frequency carrier), and the eNB can utilize one (as in E-UTRAN Rel-8) or more cells (in an aggregated manner) when assigning resources and scheduling the UE.
In current 3GPP LTE specifications there are band-specific network signaling (NS) values for each 3GPP LTE band, e.g., allowed additional maximum power reduction (A-MPR) values. The A-MPR for a band specifies how much power the UE needs to reduce from its maximum in certain conditions, for example, when transmitting on the band. Different NS values and related A-MPR specifications are presented in TS 36.101, Table 6.2.4-1. See further: 3GPP TS 36.101 V10.3.0 (2011 June), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio transmission and reception (Release 10)”, incorporated by reference herein in its entirety.
These NS values are specified for single-band operation and define the UE behavior in such a way that it can meet 3GPP, regulatory ACLR and spectrum emission requirements. Under the current rules, the NS values are not to be changed if a band is already deployed or is in the process of being deployed. Thus, it is not possible to add any new NS values to a band. In order to introduce a new NS value a new band needs to be defined, which is not a desired option.
Inter-band carrier aggregation (CA) was introduced in Rel-10/11. In inter-band CA, a terminal (e.g., a UE) operates on two or more bands concurrently. However, with certain band combinations some harmonic distortion and intermodulation problems can arise due to the concurrent operation on more than one band. Harmonic and intermodulation components may cause desensitization of a receiver if they hit on top of the receive band. In some inter-band CA cases, the 2nd order harmonic and/or 3rd order harmonic component of a transmitter hits another receiver band.
FIGS. 2 and 3 illustrates examples of harmonic and intermodulation interference. In FIG. 2, the 3rd order harmonic component of a Band17 (B17) transmission hits on Band4 (B4) reception. In FIG. 3, the 3rd order intermodulation component of Band13 (B13) and Band5 (B5) transmissions hits on top of the Band13 receiver.
In single band LTE operation, NS band specific NS values may be redefined in such a way that the operation meets requirements. However, operation for Inter-band CA is an evolutionary step from single band operation.
NS values can be signaled to secondary cells (SCells) at handover, as well as to the primary cell (PCell) when carrier aggregation is used. PCell and SCell are conventions referring to specific component carriers in CA. Signaling new NS values for a PCell allows the network to directly alter the NS values an UE is using. However, such techniques place additional burdens on the network and require more overhead for the related signaling.
Another power reduction method is power management maximum power reduction (P-MPR). In P-MPR, a dual mode device (e.g., using 1xRTT and LTE) may drop its UL power so that both radios can still continue to operate. Since the radios are independent of each other, the emission masks might create problems if they operate in certain bands. As an example, the 1xRTT radio could have an ongoing speech call, while the LTE radio would have data transfer. In order to operate both, a P-MPR would be applied. When P-MPR is applied, there is a mechanism in the power head room (PHR) report in Rel-10 wherein the UE indicates (e.g., by a bit) that in the PHR report being sent the UE has reduced maximum power due to P-MPR. This allows the eNB to be aware that a sudden drop in UE maximum UL power is caused by the second radio.